Slide driving linkage for metal forming press

ABSTRACT

The slide of a metal forming press is caused to rapidly approach the metal to be formed, then decelerate during the working stroke, and thereafter rapidly return to the uppermost position thereof by means of a novel linkage arrangement.

United States Patent 1191 Morita et al. July 9, 1974 [54] SLIDE DRIVINGLINKAGE FOR METAL 1,366,360 1/1921 Clouse 74/39 RMIN 2,688,296 9/1954 .Danly 6:311. 74/38 F0 G PRFIS 3,174,347 3/1965 Hecht I 74/38 [75] In en ors: os m ts i Jyousuke 3,693,463 9/1972 Gar-man 74/38 Kawach" Osaka Japan FOREIGN PATENTS OR APPLICATIONS [731 Assignees: 199999199, I York, 411,041 3/1925 Germany .1. 74/38 ShlPbulldlng and 338,075 6/1921 Germany 74/38 Engineering Co., Ltd., Osaka, Japan; part interest to each Filed: Sept. 19, 1972 Appl. No.: 290,333

US. Cl. 74/38 Quinn 74/38' Primary Examiner'--Benjamin W. Wyche Assistant Examiner-Wesley S. Ratliff, Jr.

Attorney, Agent, or Firm-Johnston, Root, OKeeffe, Keil, Thompson & Shurtleff [57] I 1 ABSTRACT The slide of a metal forming press is caused to rapidly approach the metal to be formed, then decelerate during the working stroke, and thereafter rapidly return to the uppermost position thereof by means of a novel linkage arrangement.

4 Claims, 2 Drawing Figures mmrmi 9w PIC-3.2

m xOmPm wojm DRAWING TIME SLIDE DRIVING LINKAGE FOR METAL FORMING PRESS BACKGROUND OF THE INVENTION For many years attempts have been made to increase the efiiciency of metal forming presses. There is a limit to which the speed of the press can be increased because, when the speed of the slide with the die thereon is increased the speed of the draw is also increased. When metal is to be formed or drawn by a die there is a limit with respect to the speed of the draw. If the drawing speed is too rapid the material will fracture.

On the other hand, if the entire press is slowed down to a speed which is proper for the draw, then the overall time of a given cycle will be longer than desirable. Attempts have been made in the past to increase the speed of movement of the draw slide during its approach to the metal to be formed and during the return of the slide to its uppermost position after the draw, and yet reduce the speed of the slide during the drawing operation. Relatively complicated linkage arrange-' ments have been used in the past in mechanical drawing presses for accomplishing this purpose, one example of which is the Schuler US. Pat. No. 3,229,535.

SUMMARY OF THE INVENTION The invention herein utilizes a novel form of linkage arrangement whereby the main link between the crank and the slide is divided into two'sections. The upper end of the upper link is eccentrically mounted on a driving gear, and the lower end of the lower link is connected to the slide. The two links themselves are then pivotally connected together and additional linkage means are provided whereby the connecting point between the two sections of the main link is caused to move laterally during its upward and downward movement, thereby imparting a rapid downward movement of the slide to the point where it begins the draw. The linkage is designed to slow the speed of the slide during the draw, and thereafter cause the slide to return to its uppermost position at a relatively rapid rate of speed.

OBJECTS or THE INVENTION The present invention is designed as an improvement and simplification of linkages heretofore devised for th'epurpose of accomplishing similar purposes, i. e., to increase the efficiency of a metal drawing press by enabling the slide to move at greater speed before and after the drawing operation has taken place. It is therefore one of the primary objects of the present invention to providea relatively simple and economical linkage arrangement for producing a variable speed linear movement in a slide of a metal forming press whereby the slide carrying the upper die will approach the metal to be formed at a relatively rapid rate, will then decelerate during the draw, and thereafter return to its uppermost position again at a relatively rapid rate.

A further object of the invention is to provide a novel linkage arrangement for driving the slide of a metal forming press, wherein the main link connecting a crank with the slide is formed in two parts pivotally connected together to form a joint which is capable of being moved laterally, in addition to being moved upwardly, thereby to increase the speed of movement of the slide during this period.

A further and more specific object of the invention is to provide a slide driving linkage arrangement wherein the upper part of a main dual link is connected to a crank which, in turn, is connected by a link to a bell crank lever. The pin connecting the upper and lower sections of the main link also has a further link connected to the other end of the bell crank lever, whereby the crank movement will oscillate the bell crank lever to not only raise and lower the slide, but at the same time to impart a lateral movement to the pivotal connection between the two part link.

Other objects of the invention will appear more fully as the description proceeds.

DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational schematic view showing the linkage arrangement of thepi'esent invention, and

FIG. 2 is a motion curve illustrating a comparison'between the movement of the slide in the present invention, and the movement of the slide which takes place by the use of a conventional and well known linkage arrangement.

DETAILED DESCRIPTION Referring now more particularly to the drawing, and especially to FIG. 1, there is illustrated a main driving gear indicated by the numeral 1. This driving gear is provided with an eccentrically mounted pin 2 connected to the slide 3 by means of a connecting rod or link 4. This main connecting rod or link 4 is divided into two parts. The upper part 40 is connected at its upper end to the eccentric pin 2 and the lower endof the other section 4b is connected to the slide 3. The upper and lower links 4a and 4b are connected together by means of the pin 5.

The structure is such that one end of a'link 6 is connected to the eccentric pin 2 and the other end thereof is connected to one arm of a bell crank lever, generally indicated by the numeral 7. The other arm 7b of the bell crank is connected to one end of a link 8. The other end of the link 8 is connected to the pin 5. The link 6is connected to the arm 7a of the bell crank 7 by means of a pin 9. The outer end of link 8 is connected by means of the pin 10 to the other arm 7b of the bell crank. The bell crank itselfis pivotally mounted by means of a pin 11 on a rigid portion of the frame 12.

.The center of the main driving gear I is indicated by the letter O. The center of the eccentric pin 2 is indicated by the letter A. The letters B, C, and D indicate respectively the centers of the connecting pins 5, 9, and

10. The circular dotted line indicated at a shows the path of movement of the center of the eccentric pin 2 as it moves in a counterclockwise direction. The dot dash line b illustrates the path of movement of the center of the connecting pin 5 as it moves in a path which is a combination of vertical and lateral movement.

The dotted line c and thedotted line d illustrate the arcuate paths of the centers C and D respectively of the connecting pins 9 and 10 during operation of the press.

It will be evident, upon viewing FIG. 1 and the paths of movement of various pins and linkages that, as the driving gear .1 rotates in a counterclockwise direction the eccentric pin 2 will cause an oscillating movement of the bell crank 7, and the respective pins 9 and 10 mounted thereon through the link 6. The arcuate movement of the pin 9 will cause a similar arcuate movement of the pin 10, through path d, which will thereupon impart a lateral motion to the connecting pin through the link 8. This, then, affords an up and down movement as well as a lateral movement of the connecting pin 5 and a consequent raising and lowering of the slide 3 at variable speeds.

In the position in FIG. 1 the slide 3 has reached its lower dead center position, but when the center a of the eccentric pin 2 has been rotated through approximately 120, and reaches the point Pa the center b of the connecting pin 5 reaches the point Pb on the path of movement b, whereupon the slide 3 reaches its upper dead center position.

Thereafter, until the eccentric pin 2 is moved through about240, and returns back to the position shown in FIG. 1, the slide 3 continues its downward movement. Accordingly, the slide 3 requires more time in its downward stroke and performs a variable speed movement, such as descending more slowly near the lower dead center point and ascending rapidly in the upward stroke after completion of the forming operation.

The motion curve illustrating this movement of the cycle of the slide 3 is illustrated by the solid line curve indicated at M of FIG. 2. This may be compared with the dotted line curve N which illustrates the motion of the slide of the normal crank press when the working time is equal in the up'and down movement of the slide.

The slide driving linkage arrangement according to the present invention is constructed so that the connecting rod 4, between the eccentric pin 2 and the slide 3 is divided into two separate linkages, 4a and 4b, connected together with a pin 5. A lateral movement is afforded to that connecting point through the link 6 connected to the eccentric pin and to the arm 7a of the bell crank lever 7, and through the link 8 connected to the other arm of the bell crank and to the pin 5. Thus, through this novel arrangement, the slide is caused to perform the working of the metal at slower speed, and is caused to return upwardly at a greatly increased speed.

Referring to FIG. 2, the time for one cycle of the press in the conventional and usual crank arrangement is indicated by T The time for one cycle of the press when the linkage of the present invention is used is indicated in FIG. 2 by T Thus, by comparing these two motion curves it will be evident that the time required for one cycle of the slide may be reduced from T to T and still maintain the same actual drawing or working time of the metal. It follows, therefore, that the rotating speed of the driving crank may be increased for obtaining the same speed of draw and thereby increase the efficiency and production of the press without in any way imparing the quality of the draw.

Changes may be made in the form, construction and arrangement of the parts from those disclosed herein without in any way departing from the spirit of the invention or sacrificing any of the attendant advantages thereof, provided, however, that such changes fall within the scope of the claims appended hereto.

We claim:

1. A driving linkage for reciprocating the slide of a mechanical press having a frame, comprising a. a crank, b. a rod connecting said crank to the slide, whereby rotation of said crank will reciprocate the slide, said rod being divided into two parts, wherein l. the upper part of said rod is connected to said crank,

2. the lower part of said rod is connected to the slide, and

3. the upper and lower parts of said rod are pivotally connected together to form a joint,

c. a first link connected at one end to said crank,

d. a second link connected at one end to said joint,

and

e. means connecting the other ends of said first and second links, whereby rotation of said crank for reciprocating the slide will also impart a lateral movement to said joint, thereby to impart to the slide a reciprocating movement which is relatively slow as it approaches lower dead center and relatively fast as it returns to its uppermost position.

2. A driving linkage for reciprocating the slide of a mechanical press as defined in claim 1, wherein said last named means includes a lever pivotally mounted intermediate the ends thereof at a fixed point on the frame.

3. A driving linkage for reciprocating the slide of a mechanical press as defined in claim 2, wherein said lever comprises a bell crank lever pivotally mounted at a fixed point on the frame at the juncture of the two arms thereof.

4. A driving linkage for reciprocating the slide of a mechanical press as defined in claim 3 wherein the arms of said bell crank lever form an obtuse angle. 

1. A driving linkage for reciprocating the slide of a mechanical press having a frame, comprising a. a crank, b. a rod connecting said crank to the slide, whereby rotation of said crank will reciprocate the slide, said rod being divided into two parts, wherein
 1. the upper part of said rod is connected to said crank,
 2. the lower part of said rod is connected to the slide, and
 3. the upper and lower parts of said rod are pivotally connected together to form a joint, c. a first link connected at one end to said crank, d. a second link connected at one end to said joint, and e. means connecting the other ends of said first and second links, whereby rotation of said crank for reciprocating the slide will also impart a lateral movement to said joint, thereby to impart to the slide a reciprocating movement which is relatively slow as it approaches lower dead center and relatively fast as it returns to its uppermost position.
 2. the lower part of said rod is connected to the slide, and
 2. A driving linkage for reciprocating the slide of a mechanical press as defined in claim 1, wherein said last named means includes a lever pivotally mounted intermediate the ends thereof at a fixed point on the frame.
 3. A driving linkage for recIprocating the slide of a mechanical press as defined in claim 2, wherein said lever comprises a bell crank lever pivotally mounted at a fixed point on the frame at the juncture of the two arms thereof.
 3. the upper and lower parts of said rod are pivotally connected together to form a joint, c. a first link connected at one end to said crank, d. a second link connected at one end to said joint, and e. means connecting the other ends of said first and second links, whereby rotation of said crank for reciprocating the slide will also impart a lateral movement to said joint, thereby to impart to the slide a reciprocating movement which is relatively slow as it approaches lower dead center and relatively fast as it returns to its uppermost position.
 4. A driving linkage for reciprocating the slide of a mechanical press as defined in claim 3 wherein the arms of said bell crank lever form an obtuse angle. 